1. Field of the Invention
This invention relates to a printer which carries out printing by applying ink by an ink roller onto the type at a daisy wheel, and more particularly to a printer which controls the daisy wheel in the rotation direction and an amount of rotations by means of a circumferential angle between the type to be printed and the ink roller to thereby devise an improvement in the printing speed, allow the type to be applied further exactly with ink, and enable the daisy wheel to be prevented from deformation.
2. Description of the Prior Art
Conventionally, a printer using the daisy wheel carries out printing by use of an ink ribbon, which method needs a drive mechanism for the ink ribbon and is complicated in construction. Hence, it has been proposed by the Japanese Patent Publication No. 4635 in 1983 that the ink roller unnecessary of the complicated drive mechanism is used to apply ink on the type for printing. In this case, however, there is a problem in that the printing time varies corresponding to the set position of ink roller, whereby it is an important point for the influence on the printing speed of printer what place the ink roller is to be set in. In other words, in a case where an ink roller 1, as shown in FIG. 1, is set in the position apart at a circumferential angle of 180.degree. from the printing position P on a daisy wheel 2 so that the type in proximity to the position P is intended to print, the daisy wheel 1 should be rotated at about 360.degree. to bring the type once to the ink roller set position, and after applied with ink, the type reaches the printing position P, which is not preferable because of a long time taken from a printing command given until the printing is performed. Also, in a case where the ink roller 1, as shown in FIG. 2, is set in the position apart at an angle of 90.degree. on the circumference of daisy wheel 2 from the printing position P, in order to print the type apart at about 180.degree. on the circumference from the daisy wheel 2, the daisy wheel 2 should be rotated at 270.degree. to a maximum. Hence, the above Japanese Patent Publication No. 4635 in 1983 discloses that, as shown in FIG. 3, two ink rollers 1, 1 are set apart at an angle of 90.degree. from the printing position P to increase the printing speed more than that in FIGS. 1 or 2 because the maximum rotary angle of daisy wheel 2 is 180.degree. enough, but such method cannot be said to be the best because two ink rollers are required.